Please refer to FIG. 1. A prior LED package device 9 comprises two metal supporting frames 911 and 912, an LED chip 92 mounted on the metal supporting frames 911 and electrically connected to another metal supporting frame 912 via a metallic conducting wire, and an injection-molded packaging body 93 encapsulating the LED chip 92.
Please refer to FIG. 2 for the manufacturing method of the foregoing prior LED package device comprises steps as follows:
S91: providing a mold 94 having a mold cavity 940;
S92: injecting an encapsulant 95 into the mold cavity 940;
S93: plugging an assembly of the metal supporting frames 911, 912 and the LED chip 92 into the encapsulant 95, and then curing the encapsulant 95; and
S94: performing mold release and thus obtaining a complete packaging body 9, in which the above mentioned encapsulant 95 forms the packaging body 93 via the curing process.
The method for assembling the prior LED package device 9 is: inserting the metal supporting frames 911, 912 through the predetermined perforations on a circuit board substrate (not shown in the drawings), and then soldering a portion of the metal supporting frames 911, 912 protruding out of the lower surface of the circuit board substrate to achieve electrical connection and to fix the LED package device to the circuit substrate.
Because the prior LED package device 9 is durable, and the light-emitting angle thereof is easy to be controlled via the design of a lens portion, the prior LED package device 9 is still being widely applied to various fields, wherein one of the main fields to which the traditional LED package device is applied is the outdoor digital signage.
Nonetheless, with the increasing demand of higher resolution of the outdoor digital signage, the LED package device 9 must be arranged more tightly to increase the density of the light-emitters on the circuit board substrate. In the foregoing assembling method, i.e., inserting the metal supporting frames through the predetermined perforations of the circuit substrate, the metal supporting frames are electrically connected to the circuit board substrate via utilizing the upper surface and the lower surface. The circuit on the substrate has to be designed in a complex manner in order to increase the density of light emitters. Therefore, if a new manufacturing method is provided wherein the advantage of the LED package device 9, namely the durability and the ease control of light emitted angle, is kept while the Surface-Mount Technology (SMT) is adopted as the new assembling method, thereby the LED package device being assembled on only one side of a circuit board method, it will greatly reduce the difficulties existing in the assembly process and the complexity of the circuit board design.
However, due to the limitation of prior-molding manufacturing process, the LED package device cannot stand on the ground with the metal supporting frames 911, 912 protruding out of the bottom surface of the packaging body 93. Also, the bottom surface of the packaging body 9 is uneven due to the protuberant parts around the metal supporting frames 911, 912, which are caused by capillarity phenomena.
In the prior arts, there are some improvements on the prior LED package device 9 by modifying the traditional LED package device 9 as being compatible with SMT assembling processes. For example, the U.S. Pat. No. 5,981,979 discloses a side-lying type LED package device in which the metal supporting frames cannot stand on the circuit board substrate and therefore the LED package device disclosed by U.S. Pat. No. 5,981,979 can only be assembled via SMT in side-lying manner.
Nevertheless, the metal supporting frames of this kind of LED package device need to be bent, and this kind of LED package device can only be applied to lateral emitting products.
There are also other advanced designs for similar packaging devices such as a mini bulb, which enable those package devices to stand on circuit board substrates and be assembled thereon. For example, the U.S. Pat. No. 6,045,365 discloses a device comprising a base component on which a mini bulb is mounted, and an installation body with circuit connector for the base component to be inserted in, wherein the installation body can stand. However, such devices comprise more components and have more complex manufacturing procedures.
U.S. Pat. No. 7,619,260 discloses a supporting member perpendicularly engages with the metal supporting frames. The supporting member along with the ends of the metal supporting frames enables the LED package device to stand despite the uneven bottom surface, and thus the LED package device can be assembled via SMT. However, such design also requires additional components and is demanding in the molding process.
U.S. Pat. No. 7,868,334 discloses an LED package device that is able to stand via two bent and parallel metal supporting frames, by which the packaging LED device can be surface-mounted via SMT. In this design, the metal supporting frames need to be bent to form a tridimensional standing structure, and the numerous bending operations lead to accumulated tolerance.